Invertebrates of Norwegian caves I. Gastropoda, Oligochaeta, Araneae, Acari, Amphipoda, Collembola, Coleoptera, Lepidoptera and Diptera

Abstract

The invertebrate fauna of 14 Norwegian limestone caves, 6 in the southern and 8 in the northern part of the country, has been studied with regard to species composition and regional distribution. The species are discussed with respect to their ecological classification as type of cave dwellers, viz. trogloxenes, troglophiles and troglobites. The Norwegian limestone caves can roughly be divided into two main types of ecosystems: 1. Open systems, connected directly to the surface, with rivers or brooks entering through discrete openings. 2. Infiltration systems, which are fed by ground water or seepage water from overlying material. In this study little attention has been paid to the fauna of open system caves, as most of the animals found here are brought in with the running water. More attention has been paid to caves of the second category, infiltration systems, as they have more complex and stable ecosystems. A total of 70 species belonging to 9 orders has been recorded. Of these only 19 species are characterized as troglophiles, while all the other species must be regarded as trogloxenes, several of them habitual trogloxenes, but most of them accidental ones.